Estimates and invoices
How do I post a paid invoice against an estimate when I didn't create the invoice from the estimate?
How do I post a paid invoice against an estimate when I didn't create the invoice from the estimate?

Since an Estimate is a "non-posting" transaction you can't "post" an invoice against it. That said I am not sure exactly what you are trying to do here? If you could clarify then maybe there is another way to accomplish this in QB.
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Will